$3.$ In a gas absorption process, if the gas film controls the rate of absorption and the height of the column based on the gas film condition is $12$ meters, how would the height change if the controlling resistance shifted to the liquid film, assuming the liquid film condition requires a height $1\mathrm{.}5$ times that of the gas film condition?

$4.$ For an absorption process using a packed column, if the overall gas phase mass transfer coefficient is $1\mathrm{.}2$ kg$/$ms and the liquid phase mass transfer coefficient is $2\mathrm{.}5$ kg$/$ms$,$ how does the choice of solvent affect the height of the column based on overall coefficients?